Background and Importance The absence of marketed medicines adjusted to the pathophysiological profile of the neonate often implies the preparation of personalised compounded medicines. To meet therapeutic needs and improve medicines’ stability, several vehicles have been developed and studied for different drugs. The choice of excipients is a critical point in paediatric compounded formulations (PCF), as there are limits inherent to the target population.

Aim and Objectives Evaluation of exposure to PCF excipients, according to individualised medical prescriptions to patients admitted to a Neonatal Intensive Care Unit (NICU) between September 2019 and August 2020, considering the recommended limits. Search for related adverse events (AEs) when limits are exceeded. Propose solutions for the non-conformities detected.

Material and Methods Definition of excipients to be evaluated, search of the respective recommended limits and AE reported.

Ranking PCF containing at least one of the selected excipients and calculation of its concentration in the formulation.

Analysis of prescriptions, calculation of excipient/patient daily intake and evaluation according to age recommendations.

In cases where the limits were exceeded, search the patient’s medical record for AE that may be related to exposure to the excipient.

Results Evaluated excipients: benzyl alcohol, benzoic acid/sodium benzoate, ethanol, propylene glycol (PG), propylparaben (PP), polysorbate 80 and sorbitol.

Considering the 10 selected PCF, present in 86 prescriptions corresponding to 172 exposures, only 2 of the evaluated excipients were found: PP and PG. In 52 exposures there was ingestion above recommended limits, 50 of which were of PG in neonates with less than 28 days of age. 5 records of AE described in bibliography with a causal link were found in the medical files.

Conclusion and Relevance In cases of formulations where exceeded excipient limits were detected, an alternative with a different composition or concentration should be investigated. As 50 out of 52 non-compliances were with PG, used as a solvent in the paraben concentrate, this formulation will be tested using water instead of PG. It was not possible to retrospectively confirm a causal assessment related to the AE found as these are common clinical conditions in these patients. Individualisation of medication through compounding is the right direction as it best suits the patient’s profile. However, the choice of excipients is crucial for patient safety.

Conflict of Interest No conflict of interest